Geophysics is an area of science that is becoming increasingly important. Geophysical exploration today generates very large amounts of data that must be accurately processed and displayed. Plotters such as cathode ray tube (CRT) or laser plotters are used but are slow. It is therefore recognized that the need exists for an instrument which is not only faster but provides accurate processing and display. An instrument which meets these requirements has been developed by Texas Instruments, Inc. in conjunction with Image Graphics, Inc., Fairfield, CN, and called TIADD (Texas Instruments Automatic Data Display). The instrument not only provides high quality seismic sections, aerial or satellite imagery but makes useful plots or maps. Ultra high resolution is achieved by means of electron beam recording directly onto an electron beam recording film which is a special film having a support, an electrically conductive layer, and a silver halide emulsion layer having appropriate sensitivity to the electron beam of the instrument. The conductive layer beneath the emulsion layer is present to bleed off or remove the negative change that gradually may build up on the surface of the film causing an undesired deflection of the electron beam which in turn causes a distorted record.
Trevoy U.S. Pat. No. 3,428,451 describes films said to be useful for electron beam recording. One of the films described has, in order, on a subbed polyester support (1) machine-coated cuprous iodide electrically conductive layer, (2) resin protective layer, (3) cellulose nitrate subbing, (4) gelatin subbing, and (5) gelatin-silver halide photographic emulsion. Various cuprous and silver halides, halides of other metals, etc., are disclosed as being useful as semiconductor compounds. The films described require multiple layers to separate the electrically conductive layer from the emulsion layer and provide necessary adhesion.
To obtain a useful work copy of a geophysicists record the following steps may be accomplished:
1. seismic data is acquired, e.g., on magnetic tape;
2. the data is readied for input into a suitable instrument, by way of illustration the TIADD described above;
3. an electron beam recording film is exposed in the instrument;
4. the recording film is reversal processed;
5. the processed film is enlarged, e.g., 5 to 10X on an enlarger, followed by conventional negative development; and
6. the enlarged film is contact copied onto photo paper to provide the working copy.
The electron beam recording film must have the appropriate sensitivity to the electron beam of the instrument and should be reversal processible with good Dmax and resolution. As indicated above such a recording film has a highly electrically conductive layer beneath the emulsion layer, e.g., in the range of 400 to 4000 ohms/square. The conductive layer, e.g., indium-tin oxide (ITO), may be applied to the support by a sputtering process, e.g., as described in Moore et. al. U.S. Pat. No. 3,630,873 and in an article by John B. Fenn, Jr., entitled "Sputter Deposited Thin Film Coatings For Use In Electro-Imaging", Advanced Printing of Conference Summaries' For the 40th Annual SPSE Conference, Rochester, New York, May 17-22, 1987, pp 265 to 268. Such a recording film, however, is disadvantageous because it is difficult to effectively wet anchor a gelatino based silver halide emulsion layer to the conductive layer. During wet processing of the recording film, in particular, the emulsion may become detached. The use of adhesion promoting agents, e.g., organic type hardeners such as formaldehyde, dimethylurea, glyoxal, in the emulsion layer has not been found to improve the adhesion.
It has been found that the above disadvantage can be overcome and an improved electron beam recording film obtained by incorporating into the emulsion layer a specific type compound that not only acts as an agent to bond the emulsion effectively to the conductive layer but also crosslinks the emulsion layer and any overcoat layer that may be present without affecting the general properties of the recording film.